Watertight wall of any desired length without joints constructed by cutting trenches in the ground and method for its construction

ABSTRACT

A watertight wall and method of forming a wall in the ground is provided. The wall uses a cement slurry of bentonite which will not exceed a viscosity of 20 centipoises after 48 hours of setting. Prefabricated parts are positioned in the wall after pouring and can be identically shaped.

United States Patent 1191 1111 3,820,344 Caron et al. June 28, 1974 WATERTIGHT WALL OF ANY DESIRED [56] References Cited LENGTH, WITHOUT J UNITED STATES PATENTS CONSTRUCTED BY CUTTING TRENCHES 3,197,964 8/1965 Fehlmann (it al. 61/35 IN THE GROUND, AND METHOD FOR ITS 3,l98,6l4, 8/1965 Powell 61/49 CONSTRUCTION 3,3l0,952 3/1967 Veder 6l/35 Inventors: Claude Caron, Samoreau; J Courte 61/35 Hurtado, Paris, both of France 3:452:546 M969 1 3,464,665 9/ l 969 [73] Asslgnee. gogleltggche, SocIete Anonyme, Pans, 3,465.532 M969 3,645,101 2/1972 [22] Filed: June 25, 1973 I Primary Examiner-Mervin Stein [21] Appl' 373226 Assistant Examiner-Philip C. Kannan Related US. Application Data Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, [63] Continuation of Ser. NO. l85,976, 061. v4, 1971, Zirm& Macpeak abandoned. i

[57] ABSTRACT [30] Foreign Apphcauon Priority Data A watertight wall and method of forming a wall in the Oct. 15, 1970 France 70.37236 ground is provided The wall uses a cement Slurry of bentonite which will not exceed a viscosity of 20 ceng fggg tipoises after 48 hours of setting. Prefabricated parts d b [58] Field 01 Search 61/35, 36, 39, 49, 63; are pos't'oned m the wa pourmg can e identically shaped.

8 Claims, 7 Drawing Figures WATERTIGHT WALL OF ANY DESIRED LENGTH, WITHOUT JOINTS, CONSTRUCTED BY CU'I'IING TRENCHES IN THE GROUND, AND METHOD FOR ITS CONSTRUCTION This is a Continuation, of application .Ser. No. 185,976, filed Oct. 4, 1971 now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present. invention relates to a watertight wall of any desiredlength and to a method for constructing the wall in the form of a body, consisting of at least one medium, extending continuously all along the wall without any joints. Here particularly the invention relates to a wall of this kind containing prefabricated parts and to a method for constructing the wall.

2. Prior Art i As' mentioned in the French patent application No. 7022101, a wall can be formed by introducing, into a trench in the ground, a hardening slurry and a system of reinforcing parts in the form of wire grating or prefabricated concrete parts, the slurry being a mixture of bentonite mud and cement which remains stable, homogeneous and liquid for at least 24 hours.

A suitable slurry was mentioned, for walls which need merely be watertight, that consisted of 50 to 100 kg of cement per m of wall. For walls which have to have some tensile strength a slurry was mentioned containing 100 to 300 kg of cement per m of wall.

Within the above composition range slurries can be found which are suitable for any given application. However many of the slurries which come within the above ranges are unsuitable for constructing walls by inserting prefabricated panels into the hardening slurry in the trench.

This is due to the fact that when prefabricated panels are introduced into a trench in the ground a certain gap E always remains between the surface of the panel and the earth surface of the trench, the gap containing the hardening slurry. Subsequently when the slurry has hardened and the earth has been excavated away from one side of the wall it is found that the gap E has not been completely filled by the slurry and consequently the wall is not strong enough. Settling of the ground is observed, amounting in some cases to several centimeters up to several meters away from the wall. In particular if the prefabricated parts are not adequately bonded together they can move, so that the ground behind settles to occupy the empty spaces in the gap E.

Even if the ground does not settle the wall is often not entirely watertight, so that leakage can appear at the joints between the panels.

SUMMARY OF THE INVENTION per m The mixture becoming hard within 48 hours a after the slurry is poured so that the viscosity does not exceed 20 centipoises and the tensile strength does not exceed 5 glcm 1 It has been found that walls constructed with slurries of the above composition are strong enough to withstand the earth pressure after excavation of the earth from one side of the wall, the wall being perfectly watertight due to the excellent bonding together of the prefabricated parts, irrespective of the particularnature of the prefabricated parts and irrespective of how they are assembled together.

A further object of the invention is to provide a process for constructing a watertight wall consisting of a prefabricated parts, by first of all cutting a trench in the ground, the trench being filled with a fine grained and homogeneous slurry containing 16 to 30 kg of bentonite and 160 to 300 kg of cement, per m, the mixture hardening during the first 48 hoursafter pouring to show a viscosity not exceeding 20 c'entipoises and a tensile strength not exceeding 5 glcm there being introduced into the slurry during this period the prefabricated panel or panels.

The process of the present invention allows a stable, watertight wall of high tensile strength to be constructed using prefabricated panels. This has a further advantage in that the wall can be extended by cutting an extension of the trench and filling it with a slurry of the same composition and immersing. further prefabricated parts in the slurry, the new section of wall being jointed to theinitial wall by bonding between the fresh hardening slurry and the partly hardened slurry of the initial wall.

A still further object of the invention is to provide a process of the kind mentioned above, in which trenches are first cut each having a length a little greater than the length of the system of prefabricated parts which it contains, these parts having edges which overlap each other but so as to leave gaps between the surfaces, whereupon an extension of the trench is cut and filled with slurry, this being done at a time when the slurry in the initial trench has a tensile strength between 150 g/cm and 1.5 kg/cm, and is no longer fluid enough to flow into the newly cut extension trench. The cutting of the extension trench is accomplished so as to cut away the end of the body of partly set slurry in the initial trench, whereupon the exposed edge of the outer. prefabricated part in the initial trench is cleaned, by removing the excess of partly hardened slurry, whereupon further prefabricated parts are lowered into the fresh slurry in the extension trench. These new parts are positioned so that the edge of the outer prefabricated part in the extension trench overlaps the edge of the outer prefabricated part in the initial trench, but leaves a gap between the surfaces.

Consequently after the wall has been completed, and after the earth has been excavated away from one side of the wall, the prefabricated parts, encased in a continuous body of hardened slurry form a rigid, continuous monolithic structure which is watertight andhas a high tensile strength, even though the prefabricated parts may not all be precisely in line with each other, due to the necessity to leave gaps between adjacent surfaces.

Finally a still further object of the present invention is to provide a process for constructing a wall of the type mentioned above by first cutting a first group of trenches spaced apart at intervals so as to allow a second group of trenches to be interposed between the first trenches, the first trenches containing n pillars and n-1 panels, the second trenches containing m-l pillars and m panels, the prefabricated parts being positioned so that their side edges overlap the flanged side edges of the pillars, but leaving a gap between the surfaces,

the outer pillars of the first trenches being positioned carefully so that they are vertical.

The purpose of this process is to ensure that the wall as a whole is vertical even though the intermediate prefabricated parts are not themselves strictly vertical. The method allows the intermediate parts a certain amount of tolerance in this regard due to the presence of the gaps between the adjacent surfaces.

A further object of the invention is to provide a method for constructing a watertight wall using prefabricated parts, in which the trench contains a certain number of prefabricated parts, each having a grooved side edge and a tongued side edge so that tongue-ingroove joints are formed between the parts. During the hardening of the mixture the prefabricated parts are suspended to ensure that they are vertical, each prefabricated part being positioned so as to leave a gap between the overlapping surfaces of the tongue-in-groove joint.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics of the invention will emerge better from the following detailed description, with the help of the drawing, which represents, as a non-limiting example, one version of a composite wall according to the inventionand two methods for forming the wall using prefabricated panels.

FIG. 1 is a plan view showing a group of prefabricated parts in the relative positions they occupy in a wall according to the invention;

FIG. 2 is a side elevation showing the two types of parts represented in FIG. 1;

FIG. 3 is a horizontal section taken along the line III- -III of FIG. 2, showing a trench containing a part of a wall according to the invention;

FIG. 4 is a horizontal section through a trench which has been out between two wall parts of the kind shown in FIG. 3, the new trench not yet containing the prefabricated parts;

FIG. 5 shows the trench represented in FIG. 4, but in this case after insertion of the prefabricated parts;

FIG. 6 is a side elevation showing a different type of prefabricated part; and

FIG. 7 is a horizontal section through a trench containing an assembly of panels of the kind represented in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the following description it will be assumed that a continuous wall is being built, using the prefabricated parts represented in FIGS. 1 and 2.

In FIGS. 1' and 2 the prefabricated parts 1 can be pillars which are considerably thicker and higher than the panels 2. For example, a pillar 1 can have a thickness of 0.50 m, the panel 2 having a thickness of only 0.25 m. The pillar 1 can have twice the height of the panel 2.

In FIG. 3 a first section of trench 3 contains n pillars and n1 panels, there being in this case two pillars 4 and 5 and between them a panel 6. It will be observed that a gap remains between the parts, the gap being in this case 0.05 m wide. AS represented in FIG. 2 the wall surfaces 4a, 6a, 5a are all in one plane. However it is obvious that the parts need not be lined up with great precision. According to the invention the wall is constructed as follows. To begin with, a first trench 3 is cut. This isfilled with a hardening slurry 7 having the following characteristics:

after the slurry has hardened it must show a cohesion at least as high as that of the ground in which thetrench is cut; t during the first 48 hours after pouring, the viscosity of the cast mass must not exceed 20 centipoises.

For example the hardening slurry can be a mixture containing 23. kg of bentonite per m and 230 kg of C.L.K. cement per m. Thisslurry satisfies the requirements and is perfectly suitable for filling the trench.

The slurry is poured progressively during the cutting of the trench. When the cutting of the trench has been completed and the trench contains the appropriate quantity of slurry, the prefabricated parts are lowered into the trench, that is to say, they are lowered down into the slurry in the trench. This method, that is to say lowering the prefabricated parts into a body of slurry in the trench, rather than pouring the slurry subsequently around the parts, has the particular advantage that a moisture tight wall is formed reliably, irrespective of the nature of the prefabricated parts and their method of assembly. This step is of some importance because the gaps between the prefabricated parts can be as little as a half a centimeter wide.

In the present example, after cutting the trench and filling it with the appropriate quantity of slurry, the two pillars 4 and 5 are lowered into the slurry in the trench. In this operation each pillar is suspended from two suspension points, to ensure that the pillar after lowering is truly vertical and correctly in line with the trench.

The panel 6 is then lowered between the two pillars 4 and 5, the panel also being suspended from two suspension points. It will be observed that each pillar has a projecting flange at each side over which the edges of the panel overlap.

The next operation is represented in FIG. 4. On the right in FIG. 4- a second trench 8 has been cut and filled with slurry and contains a pillar 9. The second trench 8 can be cut simultaneously with the first trench 3, or immediately afterwards. A third trench 10 is then cut, between the first two trenches. The method of jointing is as follows. In cutting the third trench 10 the inner ends of the two outer slabs of castgrouting are cut away as indicated in broken lines in FIG. 4. At the time when the middle trench 10 is cut the grouting of the two outer slabs 3 and 8 has already hardened enough to ensure that the mass cannot flow into the trench 10, the grouting being however still soft enough to allow it to be removed without difficulty from the edge faces of the pillars 5 and 9. These surfaces are cleaned, by removing the still soft grout, before filling slurry into the trench 10. A further pillar 11 is then lowered into the slurry in the trench 10, followed by panels 12 and 13, as shown in FIG. 5.

In the present example the trench 10 therefore contains ml pillars and m panels, that is to say, the pillar 11 and the two panels 12 and 13. It should be observed that if a pillar happens to deviate somewhat accidentally from the vertical, this does not influence the positions of the neighboring pillars and panels, due to the presence of the gaps between the prefabricated parts. The completed wall formed by the process according to the invention is essentially monolithic, so that after the earth has been removed from the excavation side of the wall the earth pressure cannot shift the wall,

which forms a continuous structure bonded by the hard set cement grouting.

The prefabricated parts represented in FIG. 7 are all identical. Each piece, as for example the panel 15, has a groove a running down one edge and a tongue 15b running down the other, so that a tongue-and-groove structure is obtained, the tongue 15b engaging in the groove 16a of the neighboring panel 16. However it should be observed that if the tongues and grooves fit closely together the first panel 15 must be positioned truly vertical with some precision.

The method of constructing the wall is essentially as described above. Before lowering the panel into the trench the latter is filled with the appropriate quantity of a hardening slurry 17 of the kind mentioned above. The trench 18 can be as long as desired, and can contain as many panels as desired.

It is obvious that, depending on the nature of the ground and on the grouting cement used, it can be advisable to add the usual accelerators or retarding agents to the slurry. A wide variety of these substances is known. A suitable composition capable of satisfying the prevailing requirements can therefore be found by consulting the relevant literature.

While the above description covers the preferred embodiment it is clear that a skilled craftsman can modify various features within the scope of the present invention, and therefore, the present invention should be measured only from the following claims.

What is claimed is:

l. A watertight wall formed by casting the wall in a trench in the ground, said wall comprising:

1. a hardened homogeneous slurry containing 16 to 30 kg of bentonite and 160 to 300 kg of cement per cubic meter, the hardening rate of the slurry being such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm within 48 hours after casting, and

2. a plurality of solid panels immersed in the slurry at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.

2. A watertight wall as claimed in claim 1 wherein said solid panels have abutting and overlapping surfaces and the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.

3. A process for constructing a watertight wall in the ground comprising the steps of:

1. first, cutting a trench in the ground;

2. then pouring into the trench a homogenous slurry a. containing 16 to kg of bentonite and 160 to 300 kg of cement per cubic meter,

b. the hardening rate of which is such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm within 48 hours after it is placed in the trench; and

3. then positioning a plurality of solid panels in the slurry filled trench at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.

4. A process as claimed in claim 3 wherein said solid panels have abutting and overlapping surfaces and said solid panels arepositioned such that the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.

5. A process as claimed in claim 3 and further including the steps of:

cutting a second trench adjacent the first slurry filed trench;

joining the two trenches when the slurry in the first trench has acquired a tensile strength greater than g/cm and a viscosity sufiicient to prevent the slurry from flowing into the second trench; removing any slurry from the end of the solid panel in the first trench nearest the second trench; pouring fresh slurry of the type previously specified into the second trench;

positioning a second plurality of solid panels at spaced intervals in the second trench in the same manner as before with at least one of said second plurality of solid panels located adjacent the pre fabricated part exposed in the first trench; and drying the slurry to form the finished wall.

6. A process for constructing a water tight wall in the ground comprising the steps of:

l. first, cutting a trench in the ground while 2. pouring progressively into the trench during the cutting thereof a homogeneous slurry a. containing 16 to 30 kg of bentonite and to 300 kg of cement per cubic meter,

b. the hardening rate of which is such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm within 48 hours after it is placed in the trench; and

3. then positioning a plurality of solid panels in the slurry filled trench at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.

7. A process as claimed in claim 6 wherein said solid panels have abutting and overlapping surfaces and said solid panels are positioned such that the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.

8. A process as claimed in claim 6 and further including the steps of:

4. cutting a second trench adjacent the first slurry filled trench when the slurry in the first trench has acquired a tensile strength greater than 150 g/cm and a viscosity sufficient to prevent the slurry from flowing into the second trench;

5. removing any slurry from the end of the solid panel in the first trench nearest the second trench;

6. pouring progressively into the second trench during the cutting thereof fresh slurry of the type previously specified;

7. positioning a second plurality of solid panels at spaced intervals in the second trench in the same manner as before with at least one of said second plurality of solid panels located adjacent the prefabricated part exposed in the first trench; and

8. drying the slurry to form the wall. 

1. A watertight wall formed by casting the wall in a trench in the ground, said wall comprising:
 1. a hardened homogeneous slurry containing 16 to 30 kg of bentonite and 160 to 300 kg of cement per cubic meter, the hardening rate of the slurry being such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm2 within 48 hours after casting, and
 2. a plurality of solid panels immersed in the slurry at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.
 2. pouring progressively into the trench during the cutting thereof a homogeneous slurry a. containing 16 to 30 kg of bentonite and 160 to 300 kg of cement per cubic meter, b. the hardening rate of which is such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm2 within 48 hours after it is placed in the trench; and
 2. then pouring into the trench a homogenous slurry a. containing 16 to 30 kg of bentonite and 160 to 300 kg of cement per cubic meter, b. the hardening rate of which is such that its viscosity does not exceed 20 centipoises and its tensile strength does not exceed 5 g/cm2 within 48 hours after it is placed in the trench; and
 2. A watertight wall as claimed in claim 1 wherein said solid panels have abutting and overlapping surfaces and the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.
 2. a plurality of solid panels immersed in the slurry at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.
 3. A process for constructing a watertight wall in the ground comprising the steps of:
 3. then positioning a plurality of solid panels in the slurry filled trench at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.
 3. then positioning a plurality of solid panels in the slurry filled trench at spaced intervals along the length of the trench so that the slurry forms a continuous body in contact with the exterior surfaces of said panels along the entire length of the trench.
 4. cutting a second trench adjacent the first slurry filled trench when the slurry in the first trench has acquired a tensile strength greater than 150 g/cm2 and a viscosity sufficient to prevent the slurry from flowing into the second trench;
 4. A process as claimed in claim 3 wherein said solid panels have abutting and overlapping surfaces and said solid panels are positioned such that the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.
 5. A process as claimed in claim 3 and further including the steps of: cutting a second trench adjacent the first slurry filed trench; joining the two trenches when the slurry in the first trench has acquired a tensile strength greater than 150 g/cm2 and a viscosity sufficient to prevent the slurry from flowing into the second trench; removing any slurry from the end of the solid panel in the first trench nearest the second trench; pouring fresh slurry of the type previously specified into the second trench; positioning a second plurality of solid panels at spaced intervals in the second trench in the same manner as before with at least one of said second plurality of solid panels located adjacent the prefabricated part exposed in the first trench; and drying the slurry to form the finished wall.
 5. removing any slurry from the end of the solid panel in the first trench nearest the second trench;
 6. pouring progressively into the second trench during the cutting thereof fresh slurry of the type previously specified;
 6. A process for constructing a water tight wall in the ground comprising the steps of:
 7. positioning a second plurality of solid panels at spaced intervals in the second trench in the same manner as before with at least one of said second plurality of solid panels located adjacent the prefabricated part exposed in the first trench; and
 7. A pRocess as claimed in claim 6 wherein said solid panels have abutting and overlapping surfaces and said solid panels are positioned such that the abutting and overlapping surfaces on adjacent panels are separated by gaps of at least 0.01 m.
 8. A process as claimed in claim 6 and further including the steps of:
 8. drying the slurry to form the wall. 